Bracing arrangement for bulldozer blades

ABSTRACT

A bulldozer has an upstanding blade pivotally connected to a pair of laterally spaced push arms adapted to be connected to the frame of a tractor. A connector block is pivotally mounted on the back of the blade and has one end of a diagonal brace universally connected to each side thereof. The opposite end of each brace is pivotally connected to a respective push arm.

United States Patent [191 F ryrear et al.

BRACING ARRANGEMENT FOR BULLDOZER BLADES [75] Inventors: Max D. Fryrear, Joliet; James L.

Harmon, Aurora, both of I11.

[73] Assignee: Caterpillar Tractor Co., Peoria, I11. [22] Filed: Nov. 8, 1972 [21] App]. No.: 304,765

[52] US. Cl. 172/803 [51] Int. Cl E02f 3/76 [58] Field of Search 172/801809 [56] References Cited UNITED STATES PATENTS 3,025,620 3/1962 Liess 172/803 3,049,820 8/1962 Lichti 172/803 June 28, 1974 3,395,764 8/1968 Win 172/803 3,647,006 3/1972 KfillenbaCh 172/803 3,653,450 4/1972 Rockwell et 81.... 172/803 3,656,558 4/1972 Kolinger 6. 172/803 Primary ExaminerStephen C. Pellegrino Attorney, Agent, or FirmPhillips, Moore Weissenberger, Lempio & Strabala 5 7 ABSTRACT A bulldozer has an upstanding blade pivotally connected to a pair of laterally spaced push arms adapted to be connected to the frame of a tractor. A connector block is pivotaliy mounted on the back of the blade and has one end of a diagonal brace universally connected to each side thereof. The opposite end of each brace is pivotally connected to a respective push arm.

4 Claims, 8 Drawing Figures BACKGROUND OF THE INVENTION any upstanding blade 11 having the forward ends of a pair of laterally spaced push arms 12 and 13 operatively connected to a back side thereof by pivotal connections 14 and 15, respectively. The rearward ends of Conventional bulldozers comprise a pair of laterally the push arms (not shown) are adapted to be univer spaced push arms adapted to be connected to the frame sally connected to the frame of a tractor in a convenof a tractor. A pair of horizontally disposed diagonal tional manner. A pair of tilt braces 16 and 17 have their braces are normally connected between the push arms forward ends universallyconnected to the back side of and a central portion of the blade and an upwardly eX- the blade by ball and socket connections 18 and 19 and tending tilt brace is connected between each push arm theirrearward ends connected to the push arms by pivand the blade. In conventional practice, at leastv one of otal connections 20 and 21, respectively. the tilt braces comprises a double-acting hydraulic cyl- At least one'of the braces, such as brace 16, comindcr adapted to be selectively extended to tilt the prised tilt cylinder meansin the form of a double-acting blade. hydraulic cylinder adapted to have a pressurized fluid A recurring problem with respect to such bulldozers l5 selectively communicated thereto for selectively tilting is one of preventing its push arms from being subjected the blade relative to ground level. In addition. a pair of to unduly'high bending moments, particularly encounhydraulic cylinders may be operatively connected betered when the blade is maintained in its tilted position tween the tractor and theblade in a conventional manand is subjected to substantial side thrusts. For examner to selectively raise or lower the blade. FIG. I illusple, US. Pat. Nos. 3,025,620; 3,049,820; 3,049,821, 30 trates piston rods 22 and 23 of such lift cylinders. 3,234,670 and 3,395,764, all assigned to the assignee A bracing arrangement 24 comprises a pair of diagoof this application, disclose various bracing arrangcnal brace means 25 and 26 pivotally connected to push ments adapted to alleviate the above mentioned probarms 12 and 13, respectively, by pivotal connections 27 lem. i (one shown). The diagonal brace means are universally 25 connected to opposite sides of a single connector block U R 28 by ball and socket connections 29 and 30, respec- An object of this invention is to provide an econo tively. As more clearly shown in FIG. 4, the longitudiical a HOH-COmPIX bracing arrangement a bllllnal axes of the diagonal brace means intersect at point dozer whichexhibits a high degree of structural integd i i th ent r f the connector block, on a rity and an ability to compensate for adverse forces. 30 rearward i f the blade imposed on the bulldozer blade during earthworking A Shown i FIGS, 24, the connector block has a operations. g v vertically disposed flange 31 secured thereon which is the bulldozer blade during e arthworking operations. pivotally mounted on the back side of the blade by The normally upstanding bulldozer blade has a pair pivot means comprising a first bracket 32 and a horiof laterally spaced push arms connected thereto. A sinzontally disposed pivot pin 33. Thus the connector gle connector block is pivotally mounted on a backside block is free to swing to-and-fro', normal to the blade, of the blade by horizontally disposed pivot means and under the restraint of brace means 25 and 26. The cona diagonal brace means connected to each of the push nector block is preferably wedge-shaped to generally arms and to a respective side of the conneetorblock to comprise a triangularly-shaped horizontal cross seceffectuate the above-mentioned operating desiderata. 0 tion.

The brace means are disposed to converge towards each other to have their longitudinal axes intersect on a rearward side of the blade. In the preferred embodi-. ment of this invention, a tilt cylinder isoperatively conl ected be twgep at least oneof the push arms and the backside of the blade to selectivelytilttheblade relative to the push arms.

BRIEF DESCRIPTION OF THE DRAWING Other objects of this invention will become apparent from the following description and acconfpanying drawings wherein:

. FIG. 1 is an isometric view of a bulldozer employing block and'attendant structures.

DETAILED DESCRIPTION FIG. 1 illustrates g bulldozer 10 comprising a nor- A second bracket 34 is secured to the back side of the blade and is positioned vertically below first bracket 32. The second bracket has a centrally disposed slot 35'formed therein to extend perpendicular relative to pin 33 to receive a like sha'ped key 36 secured under the connector block. Such mating slot and key means is disposed perpendicular to pin 33 to aid in preventing the connector block and pivot pin from being subjected to unduly high lateral forces imposed on the ends of the blade.

FIG. 5 is a force vector analysis depicting loads imposed on the connector block during bulldozer operation. The diagonal brace forces F (compression) and F (tension) are applied approximately on the centerline of connector block 28 and are separated transversely from each other at a distance d, and rearwardly from a center c of the connector block at a distance d Forces F and F are normally equal in magnitude, but

0 are opposite in direction, i.e., when one diagonal brace i s in tension the other diagonal brace is in compression. When diagonal brace forces F and F are brokendown into their component forces F,, F and F F respectively, forces F and F add together to form a side load on the block and forces F and F form a couple having a magnitude of F2 times d,. Since the line of action of forces F and F intersect behind the blade and preferably at center 0 of the connector block, which is positioned vertically below pivot pin 33, the couple is resisted by an equal and opposite couple comprising the sum of F plus F times d As a result, the connector block is not subjected to torsional forces. Furthermore, since the connector block is in equalibrium, F and F are resisted by equal and opposite forces P and F imposed on key 36 and flange 31, respectively.

Diagonal brace forces F and F do not give rise to a couple in the connector block since their respective lines of action (further depicting their longitudinal axes) intersect at common point c and hence concurrent at the centerline of the blade on the centerline of the horizontally disposed pivot pins at pivotal connections 14 and 15.

The sum of the moments occurring about maybe summarized as follows:

F, F COSa F F SINa F, F COSa F F SINa and F F (in magnitude) Therefore, the sum of the moments about center c 0 1+ 3) 2 2 4) 1 Expressed in geometric terms, d ((1 12) TANa (d,l2)(SlNa/COSa).

By now substituting for d F F F and F in the above equation,

(F COSa-r F COSa)(d /2)(SINa/COSa) (F SINa F SINa) d /2, or,

(E; F )(d l2) SINa (F F )(d /2)SlNa.

In essence, the above equations indicate that the moments caused by the four component forces F through F are equal and opposite and thus cancel each other out to impose a zero" moment on connector block 28.

FIGS. 6-8 illustrate a modification of the FIGS. 1-5 bracing arrangement wherein like numerals are employed to depict corresponding constructions. Modified constructions illustrated in FIGS. 6-8 are accompanied by an a. It should be noted that the basic changes accorded to the FIGS. 6-8 bracing arrangement are the elimination of second bracket 34 and key 36 (FIG. 3) whereby the lower end of a modified connector block 280 is unsupported and an elongation of a flange 31a and a bracket 32a. The bracket thus comprises parallel bearing plates which form substantial and opposed bearing surface areas with the flange to resist lateral movements of the connector block.

The force vector analysis for forces imposed on a modified connector block 280 of the FIGS. 6-8 bracing arrangement is substantially similar to that described above (FIG. However, resistance to side forces F and F (FIG. 7) creates a couple F times d which is resisted by a corresponding couple imposed on modified bracket 32a. As shown in FIGS. 6 and 7, the vertical height of the bracket has been substantially lengthened and d depicts the vertical distance between center 6 of connector block 28a and the longitudinal axis of a pivot pin 33a for the connector block.

Contact of flange 31a with the innersidewalls of bracket 32a is depicted by diagonally opposite force vectors F and P, which are vertically spaced at equal distances from a force vector F on the centerline of pin 33a. Distance d depicts the vertical distance between forces F and F Therefore, the following equal and opposite couples occur:

F 41 F d (in magnitude) What is claimed is:

1. A bulldozer comprising a normally upstanding blade, a pair of laterally spaced push arms having their forward ends connected to said blade, a single connector block being wedge-shaped to generally comprise a triangularly shaped horizontal cross section and having lateral sides diverging towards said blade, said connector block, positioned intermediate said push arms and pivotally mounted on a back side of said blade by pivot means for pivotal movements normal to said blade, and diagonal brace means pivotally connected to each of said push arms and universally connected to a respective lateral side of said connector block, vertically below said pivot means, said brace means disposed 'to converge towards each other to have longitudinal axes thereof intersect on a rearward side of said blade, said connector block having a vertically disposed flange secured thereon and said pivot means comprising a first bracket secured to the back side of said blade and a horizontally disposed pivot pin pivotally mounting said flange and bracket together, a second bracket secured to the back side of said blade, vertically below said first bracket, and a mating slot and key means formed on said connector block and on said second bracket to extend perpendicular to said pivot means for resisting lateral movements of said connector block.

2. The invention of claim 1 further comprising tilt cylinder means operatively connected between at least one of said push arms and said blade.

3. The bulldozer of claim 1 wherein said pivot means comprises a single pivot pin and wherein said axes intersect closely adjacent to and vertically below said pivot means.

4. A bulldozer comprising a normally upstanding blade,

a pair of laterally spaced push arms having their forward ends connected to said blade,

a single connector block positioned intermediate said push arms, pivotally mounted on a back side of said blade by pivot means for pivotal movements normal to said blade, said connector block having a vertically disposed flange secured thereon and said pivot means comprising a first bracket secured to the back side of said blade and a horizontally disposed pivot pin pivotally mounting said flange and bracket together,

diagonal brace means connected to each of said push arms and pivotally connected to a respective lateral side of said connector block, vertically below said pivot means, said brace means disposed to converge towards each other to have longitudinal axes thereof intersect on a rearward side of said blade and second bracket secured to the back side of said blade, vertically below said first bracket, and a mating slot and key means formed on said connector block and on said second bracket to extend perpendicular to said pivot means for resisting lateral movements of said connector block. 

1. A bulldozer comprising a normall upstanding blade, a pair of laterally spaced push arms having their forward ends connected to said blade, a single connector block being wedge-shaped to generally comprise a triangularly shaped horiZontal cross section and having lateral sides diverging towards said blade, said connector block, positioned intermediate said push arms and pivotally mounted on a back side of said blade by pivot means for pivotal movements normal to said blade, and diagonal brace means pivotally connected to each of said push arms and universally connected to a respective lateral side of said connector block, vertically below said pivot means, said brace means disposed to converge towards each other to have longitudinal axes thereof intersect on a rearward side of said blade, said connector block having a vertically disposed flange secured thereon and said pivot means comprising a first bracket secured to the back side of said blade and a horizontally disposed pivot pin pivotally mounting said flange and bracket together, a second bracket secured to the back side of said blade, vertically below said first bracket, and a mating slot and key means formed on said connector block and on said second bracket to extend perpendicular to said pivot means for resisting lateral movements of said connector block.
 2. The invention of claim 1 further comprising tilt cylinder means operatively connected between at least one of said push arms and said blade.
 3. The bulldozer of claim 1 wherein said pivot means comprises a single pivot pin and wherein said axes intersect closely adjacent to and vertically below said pivot means.
 4. A bulldozer comprising a normally upstanding blade, a pair of laterally spaced push arms having their forward ends connected to said blade, a single connector block positioned intermediate said push arms, pivotally mounted on a back side of said blade by pivot means for pivotal movements normal to said blade, said connector block having a vertically disposed flange secured thereon and said pivot means comprising a first bracket secured to the back side of said blade and a horizontally disposed pivot pin pivotally mounting said flange and bracket together, diagonal brace means connected to each of said push arms and pivotally connected to a respective lateral side of said connector block, vertically below said pivot means, said brace means disposed to converge towards each other to have longitudinal axes thereof intersect on a rearward side of said blade and a second bracket secured to the back side of said blade, vertically below said first bracket, and a mating slot and key means formed on said connector block and on said second bracket to extend perpendicular to said pivot means for resisting lateral movements of said connector block. 